Roller clutch cages provide a structural frame work that holds a plurality of rollers and springs together, both during operation of the clutch between a pair of clutch races, and during shipping, handling and installation operations. Each of a plurality of generally rectangular pockets within the cage retains a roller and spring, and the cage retains the pockets together. The structural performance of the cage is most critical during handling and installation, since the rollers and springs must resist strong dislodging forces. After installation, the rollers are completely radially retained between the clutch races, and float to an equilibrium circumferential position, under the force of its energizing spring. The cage and pocket side rails are still needed to locate and retain the rollers axially, however.
One of the most critical aspects of cage operation after installation is its conformation, meaning its ability to match itself to and within the generally annular space between the races, without binding on either one. This is especially true when the cage is molded plastic, as it typically is in newer designs. Plastic will both shrink and expand more rapidly than the surrounding steel clutch races as the temperature falls and rises, potentially binding or buckling. An older patented design, assigned to the assignee of the current invention, provides excellent conformation, but is expensive to produce because it requires slow, painstaking hand assembly. As disclosed in U.S. Pat. No. 4,054,192, the clutch cage is built up from a plurality of separately molded segments that are snap fitted together end to end with a radially directed pushing motion. The snap force is high, but, once snap fit is achieved, it has a degree of deliberate looseness or rattle built in at each joint. This allows the segments to shift freely back and forth circumferentially, within limits. Very good between race conformation is thereby achieved, but the force necessary to snap the segments together prevents easy disassembly later, if it is desired to replace one or more segments. The complex assembly motion is not one that could be easily adapted to machine methods. One piece, solid cage designs provide slots or other "flexible" junctures between pockets that allow the cage to stretch or shrink, and will work in many situations, much more cheaply. All one piece designs are inherently stiffer and less conformable than a segmented, loosely jointed design, however.